Certain types of phonic wheels can be used to provide information regarding the relative phase of propellers of turboprop engines, usually by removing one of the markers, creating a “missing tooth” which can be detected, or by adding an additional marker which is distinguishable from the other markers. Knowledge of the relative phase of the propellers can be used to perform synchrophasing, a technique used to reduce vibrations and noise experienced by passengers of the aircraft. However, synchrophasing techniques based on missing teeth tend to be inaccurate, and can require additional equipment to function correctly.
Therefore, improvements are needed.